Leprosy

Steven Doerr, MD

Steven Doerr, MD, is a U.S. board-certified Emergency Medicine Physician. Dr. Doerr received his undergraduate degree in Spanish from the University of Colorado at Boulder. He graduated with his Medical Degree from the University Of Colorado Health Sciences Center in Denver, Colorado in 1998 and completed his residency training in Emergency Medicine from Denver Health Medical Center in Denver, Colorado in 2002, where he also served as Chief Resident.

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

What is Leprosy?

Leprosy, also called Hansen's disease, is a chronic infectious disease that primarily affects the skin, the peripheral nerves, the mucosa of the upper respiratory tract, and the eyes. Leprosy can lead to progressive permanent damage of these structures, and the resulting devastating disfigurement and disability has led to the historical social stigma and isolation (leper colonies) of those affected by the disease.

Historically speaking, leprosy has existed since at least 4000 BC, and the disease was present and described in the ancient civilizations of China, India, and Egypt. The first known written reference to the disease on Egyptian papyrus dates from about 1550 BC. It is believed that leprosy was brought to Europe by the Romans and the Crusaders and that later the Europeans brought it to the Americas. For centuries, leprosy remained a poorly understood disease characterized by human suffering and social isolation.

In 1873, G.A. Hansen discovered the bacterial cause of this infectious disease. The first medication breakthrough occurred in the 1940s with the development of the drug dapsone, and later it was discovered that the bacteria which caused leprosy was more effectively killed by using multiple medications.

Leprosy is a curable disease with the use of multidrug therapy (MDT). In 1991, the World Health Assembly passed a resolution to eliminate leprosy as a public-health problem by the year 2000. The elimination of leprosy was defined as a prevalence rate of less than one case per 10,000 people in all countries, focused primarily on those where leprosy was commonly found.

In the year 2000, the global elimination of leprosy, according to the prevalence rate, was achieved. With assistance from the World Health Organization (WHO), MDT has been distributed free to all patients with leprosy since 1995. Though leprosy is still endemic in a few developing countries (primarily in the tropics), there has been a dramatic worldwide decrease in the prevalence of the disease due to this successful public-health initiative. Over the past 20 years, close to 16 million leprosy patients have been cured, and the prevalence rate of the disease has decreased by 90%.

Leprosy has been eliminated from 119 countries out of the 122 countries where previously leprosy had previously been deemed a public-health concern in 1985. Official reports from 115 countries around the world reported 232,857 new cases of leprosy in 2012, with about 95% of these cases occurring in only 16 different countries.

Countries in which leprosy is more commonly found include Angola, Bangladesh, Brazil, China, Central African Republic, Ethiopia, India, Indonesia, Madagascar, Myanmar, Nepal, Nigeria, Philippines, Sudan, South Sudan, Sri Lanka, United Republic of Tanzania, Democratic Republic of the Congo, and Mozambique.

In the United States, according to the National Hansen's Disease Registry, 294 new cases were reported in 2010, with 65% of these cases occurring in California, Florida, Hawaii, Louisiana, New York, Texas, and Massachusetts. On average, 150-250 new cases of leprosy are diagnosed each year in the United States, with most cases occurring in immigrants.

However, because the bacteria can be found in wild animals (for example, armadillos and chimpanzees), it is unlikely that leprosy will be totally eliminated like smallpox.

Leprosy Causes

Leprosy is an acquired infectious disease that can affect individuals of all ages. It is caused by the acid-fast, rod-shaped bacteria Mycobacterium leprae, which was discovered in 1873 by G.A. Hansen.

Because the bacterium multiplies very slowly, the signs and symptoms of leprosy may not develop until much later after exposure to M. leprae (ranging from several weeks to 20 years or more).

Though humans are the major reservoir and host for infection with M. leprae, other animals such as armadillos, chimpanzees, and mangabey monkeys, and macaques also serve as reservoirs of infection.

Leprosy is thought to be transmitted via droplets from the nose and mouth during close prolonged contact with affected individuals, though the exact route of transmission has yet to be proven definitively.

Not all individuals infected with M. leprae will go on to develop leprosy, because only 5%-10% of the population is thought to be susceptible to the infection for immunological reasons.

Leprosy Symptoms and Signs

The signs and symptoms of leprosy can vary depending on the individual's immune response to M. leprae. The WHO classification system uses clinical manifestations (the number of skin lesions and nerve involvement) as well as skin smear results to distinguish between forms of the disease. The two major WHO classifications are paucibacillary (PB) leprosy and multibacillary (MB) leprosy. However, within the WHO's simplified classification there can be a fairly wide range of patient presentations.

Paucibacillary leprosy

Two to five skin lesions with negative skin smear results at all sites

More than five skin lesions with or without or positive skin smear results at any site

The Ridley-Jopling classification is another classification system that is used globally in evaluating patients in clinical studies and contains five different classifications of leprosy that further define the patient's severity of symptoms and disease progression. The six different categories, in order of increasing severity of disease, include indeterminate leprosy, tuberculoid leprosy, borderline tuberculoid leprosy, mid-borderline leprosy, borderline lepromatous leprosy, and lepromatous leprosy.

In general, the signs and symptoms of leprosy may vary with the form of the disease and include the following:

Flat or raised skin lesions or nodules, often less pigmented than the surrounding skin, though they may appear reddish or copper colored

Single or multiple skin lesions that are often found on cooler parts of the body such as the face, buttocks, and extremities

It is important to note that the following findings may not be apparent for months to years after exposure to M. leprae.

Occasionally during or after the treatment of leprosy with MDT, an acute inflammatory state may be induced which requires the immediate attention of a health-care professional. Prompt management is necessary to avoid potential permanent neurologic damage from the following conditions:

Type 1 reaction (also known as reversal reaction)

This reaction may lead to new skin lesions, skin redness, and swelling of existing lesions, and nerve inflammation and tenderness.

This reaction is characterized by the appearance of inflamed painful nodules under the skin. It may be associated with fever and joint pain.

Leprosy Diagnosis

The diagnosis of leprosy is often established from the patient's clinical
signs and symptoms. A careful skin exam and neurologic exam will be undertaken
by a health-care professional. If a laboratory is available, skin smears or skin
biopsies may be obtained for a more definitive diagnosis. Skin smears or biopsy
material that show acid-fast bacilli with the Ziel-Neelsen stain or the Fite
stain can diagnose multibacillary leprosy. If bacteria are absent,
paucibacillary leprosy can be diagnosed. Other less commonly used tests include
blood exams, nasal smears, and nerve biopsies. Specialized tests can be done to
place the patient in the more detailed Ridley-Jopling classification.

Self-Care at Home for Leprosy

Prescribed antibiotics medications are the primary treatment for leprosy. Compliance with the full course of antibiotics is crucial to successful treatment.

Patients should also be educated to closely inspect their hands and feet for possible injuries sustained which may go unnoticed because of the loss of sensation.

Ulcers or tissue damage can result, leading to skin infections and disability.

Twenty-four months of treatment using rifampin, dapsone, and clofazimine daily

The WHO recommended therapy for leprosy is given significantly shorter and less often, as this treatment policy is based upon practical considerations in countries with fewer medical resources. However, the relapses with treatment according to the WHO recommendations are significantly greater than those with the NHDP recommended therapy.

Individuals who develop type 1 or type 2 reactions may require other medications.

Type 1 reaction (reversal reaction)

Treatment may include the use of corticosteroids, salicylates, and nonsteroidal anti-inflammatory drugs (NSAIDs).

Type 2 reaction (ENL)

Treatment may include the use of corticosteroids, salicylates, NSAIDs, clofazimine, and thalidomide (Thalomid).

Surgical Therapy for Leprosy

There are various surgical procedures available for certain patients with leprosy. These surgical procedures are aimed at restoring function of affected body parts (for example, correcting clawed hand deformities) and to cosmetically improving areas damaged by the disease. Amputation of affected body parts is sometimes necessary. Surgery may also be necessary to drain a nerve abscess (pus collection) or to relieve the compression of nerves.

Leprosy Follow-up

Patients should maintain close contact with their health-care professional during treatment with MDT, and periodic follow-up visits are recommended.

The WHO recommends the monthly direct supervision by a health-care professional during the administration of rifampicin.

Periodic blood testing during treatment is recommended, as well as yearly skin scrapings when possible.

The relapse rate after the administration of MDT is 1% for both types of leprosy. Therefore, patients should still be followed by a health-care professional for five to 10 years after completion of MDT.

Some patients with leprosy may require psychological counseling, physical therapy, and occupational therapy.

Leprosy Prevention

The prevention of leprosy ultimately lies in the early diagnosis and
treatment of those individuals suspected or diagnosed as having leprosy, thereby
preventing further transmission of the disease to others.

Public education and community awareness are crucial to encourage
individuals with leprosy and their families to undergo evaluation and treatment
with MDT.

Household contacts of patients with leprosy should be monitored closely for
the development of leprosy signs and symptoms.

A study demonstrated that prophylaxis with a single dose of rifampicin was 57% effective in preventing leprosy for the first two years in
individuals who have close contact with newly diagnosed patients with leprosy.

There is currently no widely used standard for using medications for the
prevention of leprosy.

Currently, there is no single commercial vaccine that confers complete immunity against
leprosy in all individuals.

Several vaccines, including the BCG vaccine, provide variable levels of
protection against leprosy in certain populations.

Leprosy Prognosis

Leprosy is a curable disease with the initiation and completion of MDT.

Treatment with MDT can prevent the disfigurement and neurologic disability
associated with leprosy.

Prognosis depends on the stage of the disease at the time of diagnosis, as
well as on the initiation and compliance with MDT.

Skin discoloration and skin damage generally persist even after treatment
with MDT.

Progression of neurologic impairment can be limited with MDT. In general,
however, there is partial or no recovery from neurologic damage already suffered
(muscle weakness and loss of sensation).

Relapse of leprosy after treatment with MDT is rare.

Leprosy is only rarely fatal.

Patients must be educated to be aware of the signs and symptoms of relapse
and disease exacerbations (type 1 and type 2 reactions).

Injury prevention is important to avoid chronic disability.

Public awareness and education campaigns are necessary for the early
identification and treatment of leprosy, in addition to eliminating the social
stigma and isolation associated with the disease.

The WHO public-health initiative has been extremely successful in working
toward the elimination of leprosy worldwide. Political and economic support
need to continue in order to sustain elimination and progress toward further
reducing the prevalence of leprosy globally.